Life involves making lots of decisions about right and wrong, and God has given us a conscience to help us make those decisions. Unfortunately the human conscience doesn't always give accurate readings. It's like a thermometer in an urban area. If you put an outdoor thermometer on the back of your house, and your house sits beside an expressway or a blacktop parking lot or another building, your thermometer can give readings 5 or 10 degrees above the actual temperature. Concrete, blacktop, and bricks absorb and reflect heat.
To get correct temperature readings in urban areas, the National Weather Service has strict guidelines for ideal thermometer exposure. In fact, the guidelines are so stringent it's almost impossible to meet them in the city. Tom Skilling, WGN-TV chief meteorologist, writes, "A thermometer (or its sensor) should be located over grass in a white, ventilated shelter 4–6 feet off the ground, at least 100 feet from all paved surfaces and at least 500 feet from any building."
Unless you meet those guidelines, you can't trust your thermometer. In the same way, under certain conditions, you can't trust your conscience to give accurate readings of God's perfect will.
